Get a carrot and cut up pieces into different shapes. Put on a blindfold or ask the person to close their eyes and put the shape in their mouth and identify what the shape is. This game worked wonders for me.
Another one that helped was when I got a teaspoon and put on a blindfold. My flatmate to put the teaspoon where my tongue needed to go to make a certain sound. I would then move my tongue to the teaspoon.
when I was a child a speech therapist had me close my eyes and I had to guess which part of my face she was touching.